First Op for the TFLM Signal Processing Ops library.
Doc linked in bug.
The Window OP is a custom signal processing OP similar to what is found in tf.signal library, but specific for integer (int16) purposes.
You can directly use this as a builtin op via the op resolver as:
* `op_resolver.AddWindow()`
* or via python as shown in `window_op_test.py`
3 testing options are provided:
* Micro(C++): `bazel run signal/micro/kernels:window_test`
* Tensorflow/Micro(Python): `bazel run python/tflite_micro/signal:window_op_test`
* Makefile(C++): `make -f tensorflow/lite/micro/tools/make/Makefile test_kernel_window_test`
BUG=[259145369](http://b/259145369)